1. Field of the Invention
The invention relates to a medical instrument which includes an elongated element preferably configured for transoral placement in a patient's stomach, and an end effector which can be positioned at one end of the elongated element and can be operated by means of a hydraulic actuating mechanism. The invention also relates to a method of operating the end effector which is attached in particular at one end of an endoscopic system.
2. The Prior Art
DE 44 35 644 B1 describes a hydraulic bending mechanism for a bending section of an endoscopic system. A similar device can also be found in EP 0 401 129 A1.
In U.S. Pat. No. 4,485,817 A there is disclosed a hydraulic bending mechanism for an end effector, where one piston is moved against a second piston to build up the pressure necessary in the hydraulic fluid for operating the end effector. Disadvantages of this hydraulic actuating mechanism are its complicated construction and the fact that this actuating mechanism can control only two defined operational states of the end effector. Stomach plication however will often require more than two operational states of the end effector, which makes the actuating mechanism unsuitable for such end effectors. A similar device is described in U.S. Pat. No. 5,361,583 A.
It is therefore the object of the present invention to provide a medical instrument with a hydraulic actuating mechanism which is simple in design and safe in operation and avoids the disadvantages of the state of the art.